GB900247A - Improvements in or relating to the detection of fission products - Google Patents

Abstract

900,247. Nuclear reactors. PLESSEY CO. Ltd. June 10, 1960 [June 19, 1959], No. 21177/59. Class 39 (4). Apparatus for detecting fission products in a fluid carrier medium comprises means for transferring the gaseous fission products from the carrier medium to a carrier gas phase, means for electrostatically precipitating from the carrier gas phase the solid radioactive daughters of the gaseous fission products, and means for transferring the precipitated daughter products to a second fluid carrier medium and transferring them to a zone remote from the carrier gas phase for measuring the radioactivity. In the apparatus shown in Fig. 1, sample water which may contain fission products is fed under pressure to a chamber 9 and passes through a porous sintered stainless steel plate 6. Clean water is fed under pressure to an electrically insulated chamber 15 and passes through a porous stainless steel plate 12, and an electric field is maintained between plates 6 and 12. If the sample water contains the gaseous fission products Krypton and Xenon these pass from the water, as it emerges from plate 6, into the gas between plates 6 and 12; some of the Krypton and Xenon will then decay into charged Rubidium and Caesium ions which will be attracted to plate 12 by the electric field and there dissolve in the clean water emerging from the plate which is collected in chamber 24. The water from chamber 24 is fed to a radiation counter and a delay tank before being returned to chamber 15. Gas may be passed through the apparatus continuously or may be stagnant during the monitory cycle and purged between cycles ; the gas may circulate through a delay tank, a heater being provided in a gas duct to cause a convection circulation.